Vanadium is an important by-product that is used almost exclusively in ferrous and non-ferrous alloys due to its physical properties such as high tensile strength, hardness, and fatigue resistance. Vanadium consumption in the iron and steel industry represents about 85% of the vanadium-bearing products produced worldwide. The ubiquitous vanadium is employed in a wide range of alloys in combination with iron, titanium, nickel, aluminum, chromium, and other metals for a diverse range of commercial applications extending from train rails, tool steels, catalysts, to aerospace. The global supply of vanadium originates from primary sources such as ore feedstock, concentrates, metallurgical slags, and petroleum residues. Vanadium-bearing host minerals consist of carnotite, mottramite, patronite, roscoelite, and vanadinite. Deposits of titaniferous magnetite, uraniferous sandstone, bauxite, phosphate rock, crude oils, oil shale and tar sands host vanadium. Apart from titanomagnetite and ilmenite ore deposits containing vanadium, slags from the ferrous industry are a major source of supply.
Several properties of vanadium including high melting point, low density, and relatively high strength, make vanadium a valuable metal in several industries, including steel, aerospace, chemical and battery. Previous studies have indicated that about 90% of vanadium consumption comes from steel applications, as adding less than 1% of vanadium to steel increases its tensile strength and high-temperature strength. In the aerospace industry, vanadium is used as an alloying element for titanium alloys due to its high strength to weight ratio. For example, Ti-6Al-4V titanium alloy is widely used since it shows high strength, good toughness, and high temperature stability. In the chemical industry, vanadium pentoxide is often used as a catalyst, such as sulfuric acid production and selective catalytic reduction of NOx in power plants. A vanadium redox battery is another industrial application of vanadium since it can exist in solution as four oxidation states. A vanadium redox battery is a type of rechargeable battery which has extremely large capacities, and vanadium redox batteries may also be completely discharged without ill effects. Therefore, it is ideal for use in wind or solar energy storages.